Workers on the Virgin East Coast trainline have voted to strike in a dispute over jobs, working conditions and safety.
Members of the Rail, Maritime and Transport union (RMT) backed walkouts by 84%, with nine out of 10 supporting other forms of industrial action.
The union, which is embroiled in a bitter row at Southern Railway over the role of conductors, said its executive will consider the Virgin vote.
The company said it will run a full timetable during any strike.
The two sides are in dispute over staffing changes, which the company says would have no impact on safety and no compulsory job losses.
The RMT says a package of cuts was being "bulldozed through" by Virgin East Coast (VTEC).
General Secretary Mick Cash said: "RMT will not sit back while nearly 200 members' jobs are under threat and also conditions and safety are put at risk by a franchise which is clearly in financial trouble.
"RMT is aware that VTEC management are putting out regular propaganda messages to their employees, to justify the company's attempts to attack job security, terms and conditions of employment and current working practices.
"Long-standing agreements between our two organisations dictate that the company must negotiate with RMT, as a recognised trade union to those agreements, yet the company say these changes are a consultative process.
"The company have chosen to treat the negotiations as a game thus far, merely going through the motions of pretending they did not yet know what their plans entailed. To behave like that is to treat the union and its members with pure contempt.
"Our members will not pay the price for a crisis cooked up in the Virgin boardroom. We will now be considering the massive mandate for action delivered by our members in this ballot and the union remains available for serious talks."
David Horne, Virgin Trains managing director on the East Coast, said: "We have worked hard to ensure there are comprehensive contingency plans in place and I want to reassure our customers that the timetable will be unaffected, should any strike go ahead.
"The changes we are making are part of the customer-centric revolution we have planned for the East Coast. We're already half-way through our complete refresh of our trains with all new interiors being rolled out, and in two years will have our brand-new Azuma trains coming into service. Alongside more modern trains, we want a modern customer service proposition - one that focuses firmly on the customer.
"With our guarantees that there will be no compulsory redundancies, no impact on safety and a full timetable in place during any action, we urge the RMT not to call a strike which will cost its members pay for no reason, and to rejoin us around the negotiating table."